23 tests verifying that each background worker degrades gracefully
when its dependencies are unavailable, and that failures don't cascade:
- Collector: Docker unavailable, no state file, empty fleet
- Ingester: missing log file, unset env var, malformed JSON, fatal DB
- Attacker: DB errors, empty database
- Sniffer: missing interface, no state, scapy crash, non-decky traffic
- API lifespan: all workers failing, DB init failure, sniffer import fail
- Cascade: collector→ingester, ingester→attacker, sniffer→collector, DB→sniffer
